'Crystallisation in a pudding dish'. This is a teacher-led demonstration of the formation of regular patterns with spherical objects, akin to the way in which crystal lattices may be produced in nature. The regular pattern formed by the sweets represents the arrangement of atoms in a crystal. The longer the time available for the spheres to form such a lattice, the bigger and better formed the crystal will be, as shown by the quartz crystals and regular arrangement of the sweets in the photo above. The volcanic glass shown has no crystalline structure at all; the sweets have had no time to form a regular lattice. One of the great advantages of this activity is that you can eat the chocolates at the end!
This is one of several activities about crystallisation - see the related activities listed on our home page.